I hear a short vibration/rattle noise when I increase the speed gradually to 2100 rpm. I've noticed it more with the higher gears (I have a manual transmission) because it takes a little longer to climb up the rpm's. Does anyone have any clue what this could be caused from?

There is no noise when I shift down or go down in rpm, just when it slowly increases.

Thank you.

 

Hello Fezz,
I hope some recognizes the issue from your description.
You may want to enlist the assistance of a front seat passenger or two for assistance in sound origin/direction.

best regards,
Bill